The invention relates to a diagnostic device for checking a control signal wire between a controller of a motor vehicle and a motor vehicle-side charging terminal for a battery of the motor vehicle. In addition, the invention relates to a motor vehicle and a method for detecting a defect of a control signal wire.
Motor vehicles with an electric motor are already widely known in the art, in particular in form of electric motor vehicles or, if they additionally include an internal combustion engine, in form of hybrid vehicles. A battery, usually a high-voltage battery, is provided in the vehicle for operating the electric motor of the motor vehicle. The battery can be charged by suitable charging devices (charging stations) located outside the motor vehicle.
Motor vehicles therefore usually have as part of the charging infrastructure a vehicle side charging port (charging socket), into which a plug of the charger can be plugged. The charging port is connected or can be connected to the battery via a single wire or a three-phase wire to allow charging of the battery; in addition, however, a control signal wire (“control pilot”, abbreviated as CP) is usually present to enable the exchange of control signals. On the one hand, a charge-ready state of the motor vehicle can be communicated to the charging device via the control signal wire; however, additionally or alternatively, it is also possible to communicate over the control signal wire that the charging device is ready to supply power to the motor vehicle. For example, pulse-width-modulated control signal can be used to exchange information.
On the motor vehicle side, the control signal is evaluated and/or generated in a controller, for example a charging controller and/or battery controller, which includes a corresponding logic device.
If the control signal is not present, for example due to a defect in the control signal wire between the controller and the charging port and/or due to a defect in the charging cable or on the side of the charging device, charging is usually not possible. In particular, however, it is presently not possible to determine whether a fault has occurred in the vehicle itself or in the charging infrastructure, specifically, for example, in the charging cable and/or in the charging device.